Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Jul 22, 2014 11:38:23 GMT
The problem is that most listening actually uses only a few watts. Agreed, but that's not what we are discussing here. It's the ability of your system to handle peaks without compression or clipping. Yes I understand but what I am trying to say is that in practice clipping or compression is not necessarily audible in real domestic circumstances using lower powered amps. The question is will many people benefit from going for expensive higher power amps as the formula suggests. You could go for a cheaper lower quality high power amp and have worse sound irrespective of eliminating clipping or not. |
|
|
|
Post by MartinT on Jul 22, 2014 11:53:28 GMT
Yes, I agree with that. I would never advocate watts over other parameters. I think clipping is not audible as such, but I hear lots of limiting in systems that I've heard, where the peaks simply cannot attain their natural level and the system sounds lacking in dynamics or 'sat upon'.
The worst example is a Mini-T amp driving my nearfield speakers on my computer. It simply cannot reproduce the peaks necessary - not surprising on a 14V DC supply. How anyone can use one on a main system at anything other than very low volumes is beyond me.
|
|
|
|
Post by MartinT on Jul 22, 2014 12:01:05 GMT
One point worth mentioning is the variety of tools available to ordinary listeners now that the hand-held computer is ubiquitous. I mean, of course, mobile phones.
There are plenty of apps that will give you an indication of sound pressure levels, frequency spectrum and oscilloscope displays. Even seismograph apps showing vibrations on surfaces. Many cost little or nothing, so experiment away. Knowledge is power!
|
|
|
|
Post by MikeMusic on Jul 22, 2014 12:50:20 GMT
Throwing in another wrinkle - can you throw a wrinkle ?
I've been using a db Meter for years, measuring simply the number of the volume I was listening at and using it when comparing kit to make sure I was at the same volume for each.
There was a big change when I put in the Pass Pre Amp and then another adding the Chord to the already upgraded system.
The db meter still says the same figures, but my ears say it is *louder*, due to the increased dynamic range and or lowered noise floor
I certainly appreciate the lack of effort the Chord has driving the Isobariks so I'll take what was once regarded as silly amounts of power as it seems to work very well
|
|
|
|
Post by MartinT on Jul 22, 2014 12:56:38 GMT
Change your meter's setting to read peaks and you may be surprised, Mike.
|
|
|
|
Post by MikeMusic on Jul 22, 2014 14:46:53 GMT
I will. Are you saying it *will* be louder ?
I've also checked upstairs and the sound isn't being heard at that same db figure
|
|
|
|
Post by danielquinn on Jul 22, 2014 15:01:36 GMT
It may be depending on how it works - for instance it may provide average db by taking readings over time and thus peaks may be lost .
And "I've also checked upstairs and the sound isn't being heard at that same db figure"
Ceiling effects  |
|
|
|
Post by yomanze on Jul 22, 2014 15:11:03 GMT
Interestingly watts don't really tell the whole story. There is a big difference between the demands of a sine wave being measured and real music demands. This is why some low wattage amplifiers on paper can appear to have powerful sound in reality. There are two important factors here, one is how much low level signals are preserved in the presence of musical peaks demanding a lot of power, and the second is an amp's short term current delivery. I recall Richard Bews of LFD mentioning that only 5W on paper can reproduce short peaks of 100W. Or as mentioned by Dr. Bews:
"This [Watts] is measured as continuous power rating using sine wave, which is not very relevant. More relevant is short term current delivery (10ms) peak current is around 30A for 8 ohm or 4 ohm load. This tells you that the amp can dump power into a pair of loudspeakers if required, i.e. when musical peaks occur.
|
|
|
|
Post by danielquinn on Jul 22, 2014 15:18:01 GMT
This is the problem with most measurements in hifi , they aint designed for measuring music .
Thd is a measurement at 1 frequency [ usually 1khz] and there is of course plenty of 1khz music .
Tony Benn ,famously asked - What power have you got?
Where did you get it from?
In whose interests do you use it?
To whom are you accountable?
How do we get rid of you?
The hifi equivalent
what is the measurement? , what does it measure , how does it manifest itself , what is it supposed to tell my about my experience of listening to music on my hifi and how does it do that ,
I guarantee anybody answering these questions accurately and honestly and your only retort will be - That's rubbish and you ignore measurements
|
|
|
|
Post by MartinT on Jul 22, 2014 15:57:32 GMT
I will. Are you saying it *will* be louder ? The meter in its default 'on' mode reads averages. If you change to peak (Max on the Radio Shack), it will read the loudest moments in the music. Unless you are listening to a steady-state waveform, the peaks will always be louder than the average. |
|
|
|
Post by MartinT on Jul 22, 2014 16:00:21 GMT
Interestingly watts don't really tell the whole story. There is a big difference between the demands of a sine wave being measured and real music demands. This is why some low wattage amplifiers on paper can appear to have powerful sound in reality. There are two important factors here, one is how much low level signals are preserved in the presence of musical peaks demanding a lot of power, and the second is an amp's short term current delivery. I recall Richard Bews of LFD mentioning that only 5W on paper can reproduce short peaks of 100W. Or as mentioned by Dr. Bews: "This [Watts] is measured as continuous power rating using sine wave, which is not very relevant. More relevant is short term current delivery (10ms) peak current is around 30A for 8 ohm or 4 ohm load. This tells you that the amp can dump power into a pair of loudspeakers if required, i.e. when musical peaks occur. Good post, Neil. |
|
|
|
Post by MartinT on Jul 22, 2014 16:03:07 GMT
what is the measurement? , what does it measure , how does it manifest itself , what is it supposed to tell my about my experience of listening to music on my hifi and how does it do that
Interpretation of measurements is the next most important thing after getting the measurement accurate. Interpreting measurements of music has yet another layer of difficulty. However, listening to music and having a sound pressure meter or phone with app beside you teaches you a lot more than if you didn't have them. |
|
|
|
Post by John on Jul 22, 2014 16:12:01 GMT
I use high sensitivity speakers 96db I do find I have to use the extra gain setting to get the realistic sound levels I sometimes enjoy. I also get a quite lifelike sound with plenty of resolution scale speed dynamics and scale but will also do level detail better than most systems.
I think no one would describe my system as lacking dynamics
I think you have to be careful with the db approach and agree with Tony seemed to be mostly a sales exercise I remember at the time a lot of debate mostly not so positive at the time.
Interesting debate
|
|
|
|
Post by yomanze on Jul 22, 2014 16:20:45 GMT
Regarding Musical Fidelity's campaign it is very interesting that they moved from 500W and 1000W monsters to 30W and 50W pure Class A designs. They marketed "Superchargers" as transparent and necessary to achieve proper dynamic range without clipping, and then 180ed on this with their new lines. No wonder they have been falling out of favour to some, I would love to hear one of their newest amps though.
|
|
|
|
Post by pinkie on Jul 22, 2014 16:34:10 GMT
I have a pair of high sensitivity speakers too. I did the calculations for the Lowthers, at Martins listening levels - 100db peak, 6db headroom, 2.5m (I'd be in the garden) - 12 watts needed. Using my 3db headroom and 95db peak 2 watts. No wonder the speakers sound so dynamic. And most of the time the amp driving them will be in class A! Needs a bit more heft to drive the ESL63's though!  |
|
|
|
Post by MartinT on Jul 22, 2014 16:50:03 GMT
That's why Lowthers and single-ended designs work so well together.
|
|
|
|
Post by danielquinn on Jul 22, 2014 17:12:47 GMT
what is the measurement? , what does it measure , how does it manifest itself , what is it supposed to tell my about my experience of listening to music on my hifi and how does it do that
Interpretation of measurements is the next most important thing after getting the measurement accurate. Interpreting measurements of music has yet another layer of difficulty. However, listening to music and having a sound pressure meter or phone with app beside you teaches you a lot more than if you didn't have them. Interpretation of measurement is of course an oxymoron. My avatar is 7 months old a and is 62 cm high. Interpretation what Interpretation. |
|
|
|
Post by walpurgis on Jul 22, 2014 18:18:24 GMT
Has anybody mentioned that the short term peak power of well designed amplifiers on transient signals is often many times the 'rated' power output.
|
|
|
|
Post by MartinT on Jul 22, 2014 18:29:28 GMT
Yes, Neil did above.
|
|
|
|
Post by walpurgis on Jul 22, 2014 19:13:29 GMT
Ah well, I was just skimming through. Very slack of me I know.  |
|
